Pocket thermometer depends on the extension of liquid. The liquid can be mercury or colored alcohol. This type of thermometer is universal. It can be used for temperature measurement of liquids, air, gases and solid phone It can be attached to the suction line during the overheating of measurement. For practical purposes, it can operate in wet or dry. This type of thermometer can withstand extremely aggressive fluids and environments.
When glass thermometer for reference temperature accurate if the proper contact between the stem and medium sized. Refrigeration service of persons who are familiar with the need to attach a thermometer firmly suction line when making overheating indications. Cm. Fig. 1-27A and B. Clips exist. One thing you should keep in mind that the depth at which the thermometer to be immersed in the medium being measured. Most of the instructions on to note that with liquids thermometer should be shipped so many inches. When used in a duct, the specified length of the stem should be in the flow.
Dipping only a light bulb in a glass of water does not give the same testimony as a dive in the prescribed length.
Shielding is often overlooked in the application of the simple glass thermometer. The device must be protected against radiation heat. Heating repairpersons often measure the temperature of the air in the oven hood. Do not place the thermometer in a position where it receives the direct radiation from the surface of the heat exchanger. This results in erroneous readings.
The greatest mistake is to use glass thermometer is something that is often not read. It is removed from the outlet grille packaged Air conditioning. Then she was brought to the level of the eyes in the room at the temperature of the environment. Here he read a few seconds to a minute later. It is read in a temperature different from the one in which it was measured.
Fluid temperature in the bathroom reading is taken with lamp, in the bath. You can leave for a few minutes, buried, and raised so that it can be read. A simple rule helps to eliminate the incorrect readings:
Repeatable problems with mercury-glass thermometers separation of mercury. Cm. Fig. 1-28. This results in what is often called a split thermometer. The reason column splitting the rough handling. Such treatment cannot be avoided at all the time in service work. The division is not in thermometers, who do not have gas in the atmosphere mercury. Such thermometers allow mercury to move back and forth under the influence of gravity, as well as changes in temperature. Such thermometers can not be used other than in a vertical position.
- Read in-glass thermometers while they are actually in contact with the measured medium.
- If the thermometer should be handled as little hand contact as possible. Read thermometer immediately!
Split-thermometer can be repaired. Most of the rooms thermometers mercury in the reservoir at the bottom of the tube. In this case, the cold thermometer bulb in shaved ice. It attracts mercury at the bottom of the reservoir. Add more ice or salt to reduce the temperature, if necessary. With a thermometer in a vertical position, press the bottom of the lamp on the soft piece of paper or cloth. Trapped gases causing a split column should then climb to the top of mercury. After column joined, test the service thermometer against the standard thermometer. Do this in several temperatures.